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Title:. The Application of a Piezoelectric Actuator for Forming Surface Micro-Geometries (SMG’s). By: Baharozan Mohid. Supervisor: Prof Raj Balendra. Introduction. In the recent research.
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Title: The Application of a Piezoelectric Actuator for Forming Surface Micro-Geometries (SMG’s). By: Baharozan Mohid Supervisor: Prof Raj Balendra
Introduction In the recent research Piezoelectric actuator was used for the construction of the tool-system in the creation of surface micro-geometries (smg’s) with a depth of 1 to 15 microns gives a promising results. Nevertheless To produce such accurate smg’s, very accurate displacement and consistent performance of the piezoelectric actuator is require. Therefore, loss of performance after long-term operation should be taken into account.
Introduction (cont…) Research Aim To define the decay characteristics of piezo-actuators in the view of design and develop the auto-compensation methodology Research Objectives Design and develop test equipments for establishing the decay characteristics evaluations of piezo-actuators Conduct performance trials on different prescriptions of piezo-actuators
What is Piezo-Actuator? Fig. 1: Photograph of Piezo-Actuator manufactured by Noliac A/S
Free Stroke External Spring t n Characteristic curve e ] s m n e o c r c a i l p m s [ U i o D U 1 U 2 U = 0 V 3 Blocking Force , Fmax Force [ N ] Piezo-Actuators Characteristic Uo > U1 > U2 > U3 Fig. 2: Graph of Displacement Vs. Force: Piezo-Actuator Characteristic
Characteristic Decay Phenomenon of Piezo-Actuators Definitions • Characteristic decay as a function of time is usually called “degradation” or “ageing”. • The term “fatigue” has been used by numerous researchers to describe the loss of performance of piezoelectric materials, which is due to electrical or mechanical loading.
Characteristic Decay Phenomenon of Piezo-Actuators (Cont.) “Piezoelectric materials are commonly made from poled devices, which can readily dipole by applying high electrical field, and mechanical stress”. [Dr Markys G Cain, at. el (1998)].
Characteristic Decay Phenomenon of Piezo-Actuators (Cont.) “The loss of performance of piezoelectric actuator is usually logarithmic and manufacturers will quote the lost of performance in terms of percentage loss per decade”. [B. AndresenNoliac A/S, Kvistgaard, Denmerk)].
The TechniqueofDegradation Evaluation of Piezo-Actuator • Force/Displacement Characterisation • Measurement of Free Stroke • Measurement of Blocking Force • Measurement ofCapacitance
Capacitance Measurement Force/Displacement characteristic measurement Long-Term Cyclic Test for specific number of cycles Measurement Methodology Measurement Flow Fig. 3: Measurement flow of decay characteristics of Piezo-Actuators
Test Equipment Measurement Methodology (cont….) Fig. 4: Test equipment setup for establishing the decay characteristics of Piezo-Ceramics
Measurement Methodology (cont…) Characteristic Measurement Fig. 5: The steps of characteristics measurement
Actuator 1 5 X 5 X 20mm3 SCMAS/S1/A/005/0,020/200/025/01000 : 5 X 5 X 20mm3 Actuator 2 (SML-05-28) Actuator 3 1000 800 600 Capacitance [nF] 400 200 0 7 0 14 28 42 49 63 77 84 91 98 21 35 56 70 105 Number of Cycles in Millions Actuator 1 SCMAS/S1/A/005/005/0,040/020/052/01000 : 5 X 5 X 40mm3 Actuator 2 (SML-05-29) 5 X 5 X 40mm3 Actuator 3 2.00 1.50 Capacitance [uF] 1.00 0.50 0.00 0 7 98 77 84 91 63 14 21 28 35 42 49 56 70 105 Number of Cycles in Millions Capacitance as a function of number of cycles Results
Actuator 1 SCMAS/S1/A/005/0,020/200/025/01000 : 5 X 5 X 20mm3 Actuator 2 (SML-05-28) Actuator 3 30 25 20 Free Stroke [microns] 15 10 5 0 0 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 Number of Cycles in Millions SCMAS/S1/A/005/005/0,040/020/052/01000 : 5 X 5 X 40mm3 Actuator 1 (SML-05-29) Actuator 2 Actuator 3 70 60 50 Free Stroke [microns] 40 30 20 10 0 0 7 77 84 91 98 14 21 28 35 42 49 56 63 70 105 Number of Cycles in Millions Free Stroke as a function of number of cycles Results (cont…)
Actuator 1 SCMAS/S1/A/005/0,020/200/025/01000 : 5 X 5 X 20mm3 Actuator 2 (SML-05-28) Actuator 3 1000 800 Blocking Force [N] 600 400 200 0 0 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 Number of Cycles in Millions Actuator 1 SCMAS/S1/A/005/005/0,040/020/052/01000 : 5 X 5 X 40mm3 (SML-05-29) Actuator 2 Actuator 3 1000 800 Blocking Force [N] 600 400 200 0 0 7 63 70 77 84 91 98 14 21 28 35 42 49 56 105 Number of Cycles in Millions Blocking Force as a function of number of cycles Results (cont…)
Base on the preliminary results, after applying 108 cycles of cyclic voltage of 200V (4kV/mm), the piezo-actuators maintained its excellent characteristics with no degradation (decay characteristic) of the free stroke, blocking force and capacitance Conclusionand Future Works In order to observe the degradation trends, it is beneficial to evaluate the piezoelectric actuators under the higher mechanical load condition
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